1. Field of the Invention
One embodiment of the present invention is directed to a battery time monitoring system for a cellular telephone. More particularly, one embodiment of the present invention is directed to a battery time monitor for a cellular telephone which provides the user with visual feedback as to the amount of time remaining for operation of the cellular telephone so that the user may determine how long the next call can last before the battery is discharged.
2. Description of Related Art
Cellular telephones are rapidly becoming commonplace. Indeed, in many fields a cellular telephone is almost a necessity. As cellular telephone technology advances, the size of cellular telephones is constantly shrinking to the point where cellular telephones can fit in the palm of the hand or a shirt pocket. However, one of the major problems associated with small, hand held cellular telephones is the availability of battery storage capacity for the operation of the telephone. Thus, it is often a prime concern for the user of a hand held cellular telephone to know the state of charge of the batteries in the cellular telephone.
While many cellular telephones provide an indication of the battery charge state and/or level, it is difficult for the user of a cellular telephone to convert the state of the battery into meaningful information (e.g. such as whether the battery charge state is sufficient to allow the user of the telephone to make an additional cellular telephone call, to determine the length of the call that can be made, or to determine the amount of time remaining that the user can receive calls).
An example of a battery capacity indicating system is described in U.S. Pat. No. 5,032,825 to Kuznicki entitled "Battery Capacity Indicator." In the '825 patent, a system is provided which indicates the amount of capacity remaining in the battery. However, the system described the useful battery life available does not indicate or determine the amount of remaining time for device operations. That is, the system described in the '825 patent does not give any indication to the user of a device having such a battery capacity indicating system in it how much time is available to utilize the device. Thus, although the battery capacity indicator in the '825 patent provides the user with a continuous display of the available battery capacity, such information is often of little practical value to the user of the device.
Accordingly, there is a need for a system which provides a real time display to the user of a battery operated device, based on the stored energy in the battery, of the useful battery life available.